Oh. Well sure. You'd use the mobile phone's J2ME Location API to decide where the phone is and then just go use your server-side app and tell it that data. It doesn't matter what the server side is written in - you've probably just called your server as a URL or maybe as a web service if J2ME supports that.

Most of your hard work will be writing the client-side J2ME code to access the phone's hardware via the Location API to decide what the current location is.